What stress really does to body and when it becomes dangerous

From a racing heartbeat to weakened immunity, stress can affect almost every system in the body.

While short bursts of stress are part of a normal survival response, experts warn that chronic stress can gradually damage both physical and mental health if it remains unchecked, reports The Guardian.

Why the body reacts to stress

Stress triggers the body's "fight-or-flight" response, an ancient survival mechanism designed to help humans respond to threats.

"The most immediate effect we see in a stressful situation is a surge of adrenaline causing an increase in heart rate, blood pressure and breathing," said Kavita Vedhara, a specialist in stress and behavioural medicine at Cardiff University.

Within around 30 minutes, the body also releases cortisol, commonly known as the stress hormone. According to Vedhara, cortisol helps regulate blood pressure, suppress inflammation and increase blood sugar levels to provide energy during stressful situations.

These reactions were useful when humans faced physical dangers, but modern stress often comes from emotional and psychological pressures such as work, finances, social media or family conflict.

The hidden cost of chronic stress

Experts say occasional stress is manageable because the body is built to recover afterwards. Problems arise when stress becomes constant.

During prolonged stress, the body prioritises survival systems while diverting resources away from functions such as digestion, repair and immunity.

Vedhara said chronic stress has been linked to weaker immune function, increased risk of infections, slower wound healing and reduced vaccine effectiveness.

Research has also associated long-term stress with obesity, depression and the progression of neurodegenerative diseases such as Alzheimer's disease.

How stress can create a harmful cycle

According to Jo Daniels, stress itself can make people more anxious about normal bodily sensations.

"When we're in a stress response, we're hypervigilant," said Daniels, a senior lecturer in psychology at University of Bath.

She explained that people may become alarmed by symptoms such as a rapid heartbeat or shortness of breath, which can intensify anxiety and create a cycle of fear and stress.

Stress can also impair decision-making and encourage unhealthy coping behaviours, including social withdrawal or overworking.

Who is most vulnerable?

Experts say stress affects people differently depending on personality, life experiences and resilience.

People with past trauma may have a lower threshold for stress, while others appear better able to cope with high-pressure environments.

Age and overall health also matter. Studies suggest chronic stress may have stronger effects on older adults whose immune systems are already weakened.

Can stress be managed?

Specialists say one of the simplest evidence-based ways to reduce stress is controlled breathing.

"When people are stressed or anxious, they tend to breathe in a shallow and rapid way," Daniels said. "If you breathe slowly, you're giving your brain the message that everything is OK."

Exercise can also help by reducing excess adrenaline and improving mood.

For long-term stress, experts recommend psychological therapies such as cognitive behavioural therapy (CBT), which helps people identify and challenge unhelpful thought patterns.

Mindfulness-based stress reduction techniques may also help people manage unavoidable pressures by learning to step back from stressful thoughts instead of reacting to them immediately.

When to seek help

Experts say stress becomes a serious concern when it is constant, overwhelming or begins interfering with daily life.

Daniels advised people to seek support if they feel stressed most of the time or are worried about how stress is affecting them.

Addressing the causes of stress – whether social media habits, work pressure or family conflict – is often as important as managing the symptoms themselves.